Metathesis reactions are used widely in chemical syntheses, e.g. in the form of ring-closing metatheses (RCM), cross metatheses (CM), ring-opening metatheses (ROM), ring-opening metathesis polymerizations (ROMP), cyclic diene metathesis polymerizations (ADMET), self-metathesis, reaction of alkenes with alkynes (enyne reactions), polymerization of alkynes and olefinization of carbonyls. Metathesis reactions are employed, for example, for the synthesis of olefins, for ring-opening polymerization of norbornene derivatives, for the depolymerisation of unsaturated polymers and for the synthesis of telechelic polymers.
A broad variety of metathesis catalysts are known, inter alia, from WO-A-96/04289 and WO-A-97/06185. They often have the following general structure:
where M is osmium or ruthenium, the radicals R are identical or different organic radicals having a great structural variety, X1 and X2 are anionic ligands and the ligands L are uncharged electron-donors. In the literature, the term “anionic ligands” in the context of such metathesis catalysts always refers to ligands which, when being viewed separately from the metal centre, are negatively charged for a closed electron shell.
In the meantime it has been shown that certain transition metal complexes also show catalytic activity in hydrogenation reactions of various substrates.
Well-known metathesis catalysts are for example the so-called Grubbs catalysts like Grubbs I and Grubbs II catalysts.

A lot of different catalysts have been developed and mostly the synthesis of such catalysts involves as one precursor the above mentioned Grubbs I or II catalysts.
In various publications ester hydrogenation catalysts are disclosed which all possess tridentate amino-phosphine ligands. Their preparation, however, is often extremely costly. Angew. Chem. Int. Ed. 2013, 52, 1-6 discloses the hydrogenation of low molecular weight carboxylic acid esters using different complex catalysts containing tridentate “SNS”-ligands as those shown in the following:

In Organometallics 2007, 26, 5803-5814 ruthenium alkylidene complexes of chelating amine ligands are disclosed. In particular two bidentate amino-benzyloxy ligands and two tridentate amino-bis(benzyloxy) ligands were prepared as well as ruthenium complexes containing such ligands as shown in the following scheme:

In Organometallics 2007, 26, 5803-5814 it is reported that the two catalysts bearing the tridentate [ONO] ligand display low thermal stability and low catalytic activity in RCM of diethylallylmalonate, i.e. a reasonably high conversion can be achieved only at very long reaction times (see Table 3). On the other hand Table 3 of the reference shows that metathesis activity of such catalysts increases upon addition of a Bronsted acid like HCl or H2SO4, however at the expense of an increased decomposition rate of the catalyst showing that the catalysts are less robust than desired.
In Organometallics 2005, 24, 4289-4297 Ruthenium based carbene complexes are disclosed which contain a bulky tridentate ligand, as e.g. the N,N′-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamide pincer ligand as [ONO] ligand. Such complexes are shown in the following scheme

In the ring closing metathesis of 1,7 octadiene to cyclohexene the triphenylphosphine stabilized [ONO] catalyst (4a) only showed low conversions. After 3 hours at 80° C. 76% product was observed as well as 24% isomers. Only a prolonged reaction time of up to 27 hours yielded conversion up to 98%. The presence of proton sources, i.e. Bronsted acids did not shown any influence on the catalyst activity while activation with Lewis acids even reduced the product yield drastically along with increased amounts of isomers.
Therefore, it was the object of the present invention to provide an active and robust, novel catalyst for a broad variety of reactions including metathesis and hydrogenation reactions. In particular the catalysts should not undergo a substantial decomposition under the reaction conditions and also provide acceptable conversions in reasonable reaction times compared to the slow reactions known from prior art for catalysts containing tridentate ligands.